1. Field of the Invention
The present invention relates to a laminated common mode filter including first and second coil layers with respective coils therein, and a lead layer with lead wires therein.
2. Related Background Art
Patent Document 1 below discloses a laminated common mode filter composed of a laminate and four terminal electrodes formed on the outer surface of the laminate. The laminate is formed in a four-layered structure with four layers, a first coil layer with a coil of a rectangular spiral shape, a first lead layer with a lead wire to lead one end of the foregoing coil to the terminal electrode, a second coil layer with a coil of a rectangular spiral shape, and a second lead layer with a lead wire to lead one end of the coil to the terminal electrode.
Patent Documents 2 and 3 below disclose the common mode filters of a three-layered structure in which the lead wire formed in the first lead layer and the lead wire formed in the second lead layer in the common mode filter disclosed in Patent Document 1 are formed in an identical lead layer. Patent Document 4 discloses the common mode filter in which the coils are formed in a circular spiral shape, when compared with the common mode filter disclosed in Patent Document 1.
Patent Document 1: Japanese Patent Application Laid-open No. 2005-159223
Patent Document 2: Japanese Patent No. 3601619
Patent Document 3: Japanese Patent No. 4028884
Patent Document 4: Japanese Patent Application Laid-open No. 2007-214448